Don't stop MediaPlayers before releasing them

Fixes #5298
Closes #5303

// FREEBIE

src/org/thoughtcrime/redphone/audio/IncomingRinger.java

@@ -109,7 +109,6 @@ public class IncomingRinger {
   public void stop() {
     if (player != null) {
       Log.d(TAG, "Stopping ringer");
-      player.stop();
       player.release();
       player = null;
     }

src/org/thoughtcrime/redphone/audio/OutgoingRinger.java

@@ -112,13 +112,10 @@ public class OutgoingRinger implements MediaPlayer.OnCompletionListener, MediaPl
   }
 
   public void stop() {
-    if( mediaPlayer == null ) return;
+    if (mediaPlayer == null) return;
-    try {
+    mediaPlayer.release();
-      mediaPlayer.stop();
+    mediaPlayer = null;
-      mediaPlayer.release();
+
-      mediaPlayer = null;
-    } catch( IllegalStateException e ) {
-    }
     currentSoundID = -1;
   }